替换:-e是编辑命令,用于sed执行多个编辑任务的情况下。在下一行开始编辑前,所有的编辑动作将应用到模式缓冲区中的行上。 sed-e'1,10d'-e's/My/Your/g'datafile #选项-e用于进行多重编辑。第一重编辑删除第1-3行。第二重编辑将出现的所有My替换为Your。因为是逐行进行这两项编辑(即这两个命令都在模式空间...
它允许将多个语句组合在一起执行。 5)if (表达式) statement 1 [else statement 2] if语句根据表达式的值决定执行statement 1或statement 2。如果表达式为非零,则执行statement 1。如果存在statement 2,且表达式的值为0的时候执行statement 2。 6)while ( expression ) statement while语句将在表达式为非零时执行语...
条件语句 if (expression) { statement; statement; ... ... } if (expression) { statement; } else { statement2; } if (expression) { statement1; } else if (expression1) { statement2; } else { statement3; } 循环语句 C语言:while、do/while、for、break、continue Examples: 一.命令行方式...
if…elif…else…fi语句 1、if…else语句 代码语言:javascript 代码运行次数:0 运行 AI代码解释 if[expression]thenStatement(s)to be executedifexpression istruefi 注意:expression 和方括号([ ])之间必须有空格,否则会有语法错误。 if…else也可以写成一行,以命令的方式来运行,像这样: 代码语言:javascript 代码...
awk '{for (condition) {statement} }' 3.3-数学运算 代码语言:javascript 代码运行次数:0 运行 AI代码解释 $ cat mtcars2.csv | awk 'BEGIN{FS = ",";OFS="\t"} {if ($2 == 8) {print $2-$1}} END{print "---finish---"}' | head -10.7 -6.3 -8.4 -9.3 -7.2 -2.4 -2.4 -6.7 ...
155 156 Do not unnecessarily use braces where a single statement will do. 157 158 if (condition) 159 action(); 160 161 and 162 163 if (condition) 164 do_this(); 165 else 166 do_that(); 167 168 This does not apply if only one branch of a conditional statement is a single 169 ...
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If you are upgrading from a previous SUSE Linux Enterprise Server release, you should review at least the following sections: Section 2.6, “Support statement for SUSE Linux Enterprise Server” Section 4.2, “Upgrade-Related Notes” Section 5, “Changes affecting all architectures” 2.3 Security, ...
1 switch语句和shell中的case很像，就不在演示了switch(expression) {case VALUE1 or /REGEXP/:statement1; case VALUE2 or /REGEXP2/: statement2;...; default: statementn}5.2 break和continue---奇数相加[root@along ~]# awk 'BEGIN{sum=0;for(i=1;i<=100;i++){if(i%2==0)continue;sum+...
awk [options] -f programfile var=value file… awk [options] 'BEGIN{ action;… } pattern{ action;… } END{ action;… }' file ... 4.2.2 常用命令选项 -F fs:fs指定输入分隔符,fs可以是字符串或正则表达式,如-F: -v var=value:赋值一个用户定义变量,将外部变量传递给awk ...